Nancy Pelosi, a senior Democratic leader from the US House of Representatives, on Wednesday accused China of using economic leverages to silence friends of Tibet.
Adopting a tough stand over the situation in Tibet, she said: "We will not be silenced by the brutal tactics of China.
"China uses its economic leverages to silence the voices of friends of Tibet," Pelosi, 76, said in her address at a public event here where Tibetan spiritual leader the Dalai Lama was also present.
Beijing accuses the Dalai Lama of trying to split Tibet from China.
Pelosi flew into Dharamsala on Tuesday to meet the Tibetan leader and top officials of the Tibetan government-in-exile here. Seven US Congressmen are accompanying her.
"But if we do not speak out against repression in Tibet because of China's economic power, we lose all moral authority to talk about human rights anywhere else in the world," she said.
"We will not be silenced, you will not be silenced.
"The brutal tactics of the Chinese government towards religion, culture and language of the Tibetan people challenges the conscience of the world.
"We will meet that challenge, working together we will meet that challenge."
Recalling her visit to Tibet last year, Pelosi said: "We went to the Potala Palace and we promised each other that we will do everything in our power to make sure he (Dalai Lama) returns to that place."
Praising the Tibetan government-in-exile, officially known as the Central Tibetan Administration, she said: "We saw hope for the progress of freedom for Tibet."
Pelosi, a former Speaker of the House of Representatives, is a long-time supporter of the Tibetan cause.
Besides Pelosi, the delegation included Jim Sensenbrenner, Eliot Engel, Jim McGovern, Betty McCollum, Judy Chu, Joyce Beatty and Pramila Jayapal.
"We believe in you (Dalai Lama) and stand with you," McGovern said in his address.
He urged the Trump administration to meet the Dalai Lama.
Tracing her roots to India which she left when she was 16 years old, Jayapal said "truth will always win".
The Dalai Lama lives in India along with over 100,000 Tibetans.